The North American B-25 Mitchell was an American twin-engined medium bomber manufactured by North American Aviation. It was used by many Allied air forces, in every theater of World War II, as well as many other air forces after the war ended, and saw service across four decades.
Development
The North American B-25 'Mitchell' was an American twin-engined medium bomber manufactured by North American Aviation originally designated NA-40B a twin-engined five seat bomber to meet 1938 USAAF requirement for attack bomber. Powered by two 1,100 hp (825 kW) Pratt & Whitney R-1830-56C3G radials. It required 8,500 original drawings and 195,000 engineering man-hours to produce the first one. The prototype NA-40 was first flown in January 1939 by Paul Balfour. The modified and improved NA-40B was submitted to the United States Army Air Corps for evaluation. A product of Dutch Kindelberger's North American team was to be an efficient, easy to manufacture and repair and was able to do any job assigned to it. The B-25 was named in honor of General Billy Mitchell, a pioneer of U.S. military aviation. When the production version of the B-25 first flew on August 19, 1940, the airplane had been given additional power in the form of its Wright GR-2600 engines. The initial B-25 was lacking in directional stability, and examples after number ten had the wings "gulled" to reduce the amount of dihedral (the angle between the wing and an intersecting horizontal). An improvement of the NA-40B, dubbed the NA-62, was the basis for the first actual B-25. This aircraft was originally intended to be an attack bomber for export to the United Kingdom and France, both of which had a pressing requirement for such aircraft in the early stages of World War II. However, those countries changed their minds, opting instead for the Douglas DB-7.
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Into Service
The Pacific and Far East
The majority of B-25s in American service were used in the Pacific. It fought on Papua New Guinea, in Burma and in the island hopping campaign in the central Pacific. It was in the Pacific that the aircraft's potential as a ground attack aircraft was discovered and developed. The jungle environment reduced the usefulness of standard-level bombing, and made low-level attack the best tactic. The ever-increasing amount of forward firing guns was a response to this operational environment, making the B-25 a formidable strafing aircraft.
In Burma, the B-25 was often used to attack Japanese communication links, especially bridges in central Burma. In the Pacific, the B-25 proved itself to be a very capable anti-shipping weapon, sinking many ships. Later in the war, it was used against Guam and Tinian. It was then used against Japanese-occupied islands that had been bypassed by the main campaign, like in the Marshall Islands.
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The B-25 first gained fame as the bomber used in the 18 April 1942 Doolittle Raid, in which 16 B-25Bs led by Lieutenant Colonel Jimmy Doolittle attacked mainland Japan, four months after the bombing of Pearl Harbor. Although the amount of actual damage done was relatively minor, it forced the Japanese to divert troops for the home defense for the remainder of the war. Doolittles B-25's took off from the carrier USS Hornet and successfully bombed Tokyo and four other Japanese cities without loss. Fifteen of the bombers subsequently crash-landed en route to recovery fields in Eastern China. Only one B-25 bomber landed intact, in Siberia where its five-man crew was interned and the aircraft confiscated. Of the 80 aircrew, 69 survived their historic mission and eventually made it back to American lines. Although the B-25 was originally designed to bomb from medium altitudes in level flight, it was used frequently on treetop-level strafing and parafrag (parachute-retarded fragmentation bombs) missions against Japanese airfields in New Guinea and the Philippines. These heavily armed Mitchells, field-modified at Townsville, Australia, by Major Paul I. "Pappy" Gunn and North American tech rep Jack Fox, were also used on strafing and skip-bombing missions against Japanese shipping trying to resupply their land-based armies.
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Fighting the Luftwaffe
The first B-25s arrived in Egypt just in time to take part in the Battle of El Alamein in November 1942. From there the aircraft took part in the rest of the campaign in North Africa, the invasion of Sicily and the advance up Italy. In Italy the B-25 was used in the ground attack role, concentrating on attacks against road and rail links in Italy, Austria and the Balkans. The five bombardment groups that used the B-25 in the desert and Italy were the only U.S. units to use the B-25 in Europe.
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Other Nations
The Royal Air Force (RAF) was an early customer for the B-25 via Lend-Lease. The RAF was the only force to use the B-25 on raids against Europe from bases in the United Kingdom. A total of 93 Mitchell Is and IIs had been delivered to the RAF by the end of 1942 and served with No. 2 Group RAF, the RAF's tactical medium bomber force. The first RAF operation with the Mitchell II took place on 22 January 1943, when six aircraft from No. 180 Squadron RAF attacked oil installations at Ghent. After the invasion of Europe, all four Mitchell squadrons moved to bases in France and Belgium (Melsbroek) to support Allied ground forces. The British Mitchell squadrons were joined by No. 342 (Lorraine) Squadron of the French Air Force in April 1945.
The Royal Canadian Air Force (RCAF) used the B-25 Mitchell, although most of the RCAF use of the Mitchell was postwar. The first B-25s for the RCAF had originally been diverted to Canada from RAF orders. These included one Mitchell I, 42 Mitchell IIs, and 19 Mitchell IIIs. No 13 (P) Squadron was formed unofficially at CFB Rockcliffe in May 1944. They operated Mitchell IIs on high altitude aerial photography sorties.
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Well over 100 B-25Cs and Ds were supplied to the Nationalist Chinese during the Second World War. In addition, a total of 131 B-25Js were supplied to China under Lend-Lease. The four squadrons of the 1st BG (1st, 2nd, 3rd, and 4th) of the 1st Medium Bomber Group were formed during the War.
During the World War II, the Mitchell served in fairly large numbers with the Air Force of the Dutch government-in-exile. They participated in combat both in the East Indies as well as on the European front. On 30 June 1941, the Netherlands Purchasing Commission, acting on behalf of the Dutch government in exile in London, signed contract with North American Aviation for 162 B-25C aircraft. The bombers were to be delivered to the Netherlands East Indies to help deter any Japanese aggression into the region. The B-25s of No. 18 (RAAF) Squadron were painted with the Dutch national insignia (at this time a rectangular Netherlands flag) and carry NEIAF serials. Discounting the 10 "temporary" B-25s delivered to 18 Squadron in early 1942, a total of 150 Mitchells were taken on strength by the NEIAF, 19 in 1942, 16 in 1943, 87 in 1944, and 28 in 1945. They flew bombing raids against Japanese targets in the East Indies from Australia.
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The U.S. supplied 862 B-25(of B,D,G and J types) aircraft to the Soviet Union under Lend-Lease during the Second World War via the Alaska-Siberia ALSIB ferry route. The B-25 was operated as a ground support and tactical daylight bomber and saw action in fights from Stalingrad (with B/D models) to the German surrender during May 1945 with (G/J types).
Production and Aftermath
By the end of its production, nearly 10,000 B-25s in numerous models had been built. These included a few limited variations, such as the United States Navy's and Marine Corps' PBJ-1 patrol bomber and the United States Army Air Forces' F-10 photo reconnaissance aircraft.
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P-26 Peashooter
P-36 Hawk
P-38 Lightning
P-39 Airacobra
P-40 Warhawk
P-47 Thunderbolt
P-51 Mustang
P-61 Black Widow
A-20 Havoc
A-26 Invader
B-17 Flying Fortress
B-24 Liberator
B-26 Marauder
B-29 Superfortress
North American B-25 'Mitchell'
